Antiseize lubricating compound for threads and its method of preparation



Patented F eb- 23,1943

ANTISEIZE LUBBICATENG COMPOUND FOR THREAD 8 AND ITS METHOD OF PREPARA-Arthur 1;. Parker, Cleveland, OhiO No. Drawing. Application Mitch 26,1941,

Serial No. 385,33

4 Claims. (Cl. 252-37) This invention is concerned with a composition inthe form of a thick paste or semi-solid for employment on threads andother parts formed of metals such as aluminum, aluminum alloy, etc., forservice under conditions where there may be contact with water, air andnatural 8 A preferred composition comprises the following ingredients:

Mineral oil 16 gallons (120 pounds) Fused lead stearate 28 pounds Thepreferred mineral oil is a parafline type oil having a viscosity of 140to 220 seconds by Saybolts universal viscosimeter at 210 degrees F.; andhaving a flash point of 490 degrees F. and

a fire point of 540 degrees F. Oils of a substantially less viscosity donot provide a product having the desired body, even in the presence of alarger quantity of stearate. Care should be taken to employ a neutraloil of high chemical stability for maximum advantage with threaded andlike parts of aluminum or aluminum alloy.

The fused lead stearate is a metallic soap employed for giving, whenproperly compounded with the oil, better anti-seize properties than andis preferred over fused zinc stearate because zinc stearate undergoes apartial decomposition during fusion, and the fused product does notblend into the oil in a satisfactory manner for forming a stableproduct. The lead stearate is preferred over lead oleate since thelatter has too low a melting point and is susceptible to oxidation: andlikewise is preferred to lead palmitate which has a somewhat lowermelting point than the stearate and does not lead to the stillcomposition which is presently preferred. It will be understood,however, that lead palmitate and even a minor proportion of lead oleatemay be tolerated in the material and at times employed where it isdesired to have a particular physical consistency or viscosity with arelatively high percentage of the anti-seize ingredient or metallicsoap, compared with the quantity of oil utilized.

In the above preferred composition, the ratio by weight is 81 per centof oil to 19 per cent of stearate. It is, however, feasible to employother proportions in which the stearate is present on the basis of 20 topounds per 120 pounds of oil, or roughly 13 to 23 per cent.

The lead stearate is a neutral material preferably prepared by fusingmolecularly equivalent quantities of stearic acid and (bivalent) leadoxide until chemical union occurs, and a fused product is obtained. Thisproduct is thencooled and ground until the bulk is around 40 mesh, withthe exclusion of particles in excess of 20 mesh, in order to present thestearate in such a finely divided form that it is quickly taken up bythe 011 during the blending operation. Obviously, a finer grind isfeasible, at a relatively greater expense.

The composition is most advantageously formed by heating the oil to atemperature of at least degrees 0., and preferably not exceeding degreesC- A suitable container such as an agitated grease kettle or a kettlehaving mechanical mixing device, can be employed for the operation. Theground particles of the fused lead stearate are then introduced slowlywith constant agitation, and with maintenance of the temperature. As theparticles of fused stearate 'come into contact with the oil, theyaremelted and then blended into the oil. It has been found that when alesser temperature than 130 degrees C. is utilized, or when largequantities of stearate are suddenly introduced, the 011 forms an initialcoating around a particle or a group of particles of the stearate andthat therewith a ball of unmelted stearate is maintained in spite of alengthy agitation or considerable increase of temperature, as thecoating of oil appears to act as an insulator to prevent the blending.It has, however, been found possible also to intermingle ,the stearateby slowly mixing with the oil at substantially room temperature, andthen bringthe entire mass to atemperature inexcess of 130 degrees and bycontinuously agitating produce a composition of uniform nature; but thismethod leads to foaming and sometimes to a lumping which cannot bedissipated without heating to a relatively higher temperature thanemployed with the preferred procedure.

The blending operation may be followed by observing the appearance as tofreedom from small lumps or particles of unmelted stearate which arereadily visible even into the later stages of blending. When thecontents of the kettle appear to have a uniform consistency, a spatulaor test stick is dipp d into the mixture and withdrawn. As thecomposition cools, a coating forms on the spatula, and can be rubbedbetween the fingers: if found free of lumps and smooth and uniform, theblending is satisfactorily completed, while if there is an appearance or"touch" of graininess, or the presence of small particles is observed,heating and stirring is continued until the desired smooth and uniformproduct is obtained.

The contents oi the mixing vessel are then cooled to about 100 degreesC., and packaged in cans or other suitable containers.

The preferred final product has a A. S. T. M. penetration reading of 240to 300 at room temperature (72 degrees F.). and a negative response asto corrosion of metal.

The material is employed by applying sparingly and evenly to thethreaded or other parts before assembly.

It is obvious that the invention is not limited solely to theingredients and proportions described, but may be employed in modified'form within the scope of the appended claims.

Iclaim:

1. An anti-seize paste for sealing threaded joints and like partsbetween metals, comprising a mineral oil having a viscosity of at least140 seconds Saybolt at 210 degrees F., and timed lead stearateintimately blended with the oil. the oil and stearate being presentsubstantially in the proportion by weight of 120 parts of oil for 20 to35 parts of stearate.

2. An anti-seize paste for sealing threaded joints and like partsbetween metals, comprising a mineral oil of paraffine type having aviscosity of 140 to 220 seconds Saybolt at 210 degrees F. with a flashpoint of substantially 490 degrees F. and a fire point of substantially540 degrees F.. together with fused lead stearate intimately distributedin said oil to provide a smooth and uniform paste, the oil and stearatebeing present substantially in the proportion by weight or parts of oilfor 28 parts of the stearate, the paste having an A. S. T. M.penetration reading substantially between 240 and 300 at roomtemperature.

3. The method oi! forming an anti-seize paste for sealing threadedjoints and like parts, which comprises heating a mineral oil ofparafline type having a viscosity of 140 to 220 seconds Saybolt at 210degrees F. to a temperature of to 160 degrees C., bringing finelydivided fused lead steal-ate in successive small quantities into the hotoil, stirring throughout the addition 01 stearate and until the mass isof smooth uniform consistency, the stearate being added until theproportion by weight is substantially 120 parts of oil tor 20 to 35parts of stearate, and then cooling.

4. An anti-seize paste for sealing threaded joints and like partscomprising a stable noncorrosive base consisting of a neutral mineraloil of paraiiine type having a viscosity of at least seconds Saybolt at210 degrees F., and neutral fused lead stearate intimately blended with.the oil, substantially in the proportions of 120 parts by weight ormineral oil to 28 parts by weight of fused lead stearate.

ARTHUR L. PARKER.

